Description

Gigabit Ethernet has established itself as a standard in the networking in office and industrial environments. Nevertheless, there is little information in the relevant technical literature about EMC aspects of Gigabit Ethernet interfaces. This article about the new reference design from Würth Elektronik is intended to close this gap. Here the circuit developer gets an optimized circuit design and layout with all technical data for a Gigabit Ethernet front end.

The electronics board offers two interfaces, a USB Type C™ (USB 3.1) - and a 1 Gigabit RJ45/Ethernet interface. The GB Ethernet USB adapter was developed based on Microchip's EVB-LAN7800LC - evaluation board. The circuit is built on a 4-layer PCB and in this design is powered via the USB interface. In the first part of this app note, technical basics are presented that are necessary for understanding the reference design. The second part describes in detail the 1 GB Ethernet interface up to the PHY. EMC technical aspects are covered in detail in App Note ANP116.

Contents:

• Basics of 1 Gigabit Ethernet interface
• Design and structure of an adapter board
• Important design aspects
• Reconstruction of the reference board with design data (Altium Designer / Gerber data)